Field of the Invention:
The present invention relates to essentially, typically completely inorganic settable slurries, to a process for the formulation thereof, and to the use of such slurries for sealing and/or consolidating soils and ground formations and/or construction (building) materials via injection technique.
Description of the Prior Art:
The treatment of soils and/or of construction materials via injection technique entails filling or repairing cracks, or ground imperfections, with slurries of various compositional nature intended to modify the characteristics of the ground, building material, etc., thus treated.
These modifications are concerned either with improving the mechanical properties of ground formations in the case of consolidation, or with reducing the permeability in the case of sealing. It is also possible to treat, via injection technique, for purposes of modifying these two properties.
Until recently, sealing and consolidating soils or construction materials was principally carried out by injecting organic slurries therein. However, the syneresis products of such slurries (decomposition of the chemical products injected or formed) cause contamination of ground waters and of surface waters.
Thus, the current major concern in the art of sealing and/or consolidating soils is the preservation of the quality of ground waters and of surface waters, such as water courses and reservoir waters.
This concern has prompted the use of alternate inorganic slurries.
To satisfy, technically and economically, the new constraints presented by ecological considerations, many alternatives have been proposed to this art.
Thus, French Patent No. 2,571,734 describes an injectable aqueous slurry for the consolidation and/or sealing of soils which comprises fine particles of amorphous silica and particles of slaked lime.
However, this slurry presents the disadvantage of requiring an excessively lengthy setting time (approximately 2 days).
Also, French Patent No. 2,528,441 describes a sealing and/or consolidating agent for soils comprising a concentrated sodium solution of specific silica and, optionally, of lime or a calcium salt. The dissolved silica reacts with the calcium to form hydrated calcium silicate crystals.
However, these slurries present the disadvantages either of having mechanical properties which are only marginally satisfactory, or of requiring an excessively short setting time, incompatible with the desired application, or also of being initially too viscous.